** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE AIM OF THIS PROJECT IS TO IMPROVE OUR UNDERSTANDING OF NITROGEN POLLUTION IN AGRICULTURAL WATERSHEDS ANDDEVELOP BETTER METHODS FORMANAGING AND REDUCING THIS POLLUTION. WHILE NITROGEN IS ESSENTIAL FOR ALL LIFE, EXCESSIVE AMOUNTS CAN HARM WATER QUALITY,LEADING TO PROBLEMS LIKE ALGAL BLOOMS AND POORCONDITIONS FOR FISH AND OTHER AQUATIC LIFE.IN AGRICULTURAL AREAS, NITRATE--A FORM OF NITROGEN USED IN CROP FERTILIZERS--IS THE DOMINANT SOURCE OF NITROGEN POLLUTION INSTREAMS. NITRATE MOVES FROM LAND TO STREAMS THROUGH SURFACE RUNOFF AND GROUNDWATER. THE AMOUNT OF NITRATE ENTERING STREAMS CHANGES WITH DIFFERENT CONDITIONS, SUCH AS RAINFALL.THIS PROJECT FOCUSES ON UNDERSTANDING WHAT CAUSESPOST-STORM NITRATE ENRICHMENT,LONG PERIODS OF ELEVATED NITRATE LEVELS IN STREAMSAFTER STORMS. TO STUDYTHIS, THE PROJECT USES A COMBINATION OF FIELDEXPERIMENTS, SENSOR TECHNOLOGY, AND COMPUTER-BASED MAPPING TOOLS. SENSORS PLACED IN STREAMS WILL CONTINUOUSLY MEASURE NITRATE LEVELS. DURING AND AFTER STORMS, WATER SAMPLES WILL BE COLLECTED FROMDIFFERENT SOURCES SUCH ASSTREAMS, GROUNDWATER, SURFACE RUNOFF, AND RAINWATER. ANALYZING THESE SAMPLES WILL HELP IDENTIFY THE MAIN SOURCES OF NITRATE CONTRIBUTING TO POST-STORM ENRICHMENT.THE INITIAL WORK IS CONDUCTED INTHE MAHANTANGO CREEK WATERSHED, A PRIMARILYAGRICULTURAL AREA IN PENNSYLVANIA. THE SUBWATERSHEDS OF MAHANTANGO CREEK EXPERIENCING POST-STORM ENRICHMENT WILL BE IDENTIFIED USING THE SENSOR DATA. THE SIGNIFICANCE OF THESE PERIODS WILL BE EVALUATED BY CALCULATING THE AMOUNT OFNITRATETRANSPORTED. FINDINGS FROM THESE SUBWATERSHEDS WILL BE EXPANDED TO OTHERAREAS WITHIN THE LARGER CHESAPEAKE BAY WATERSHED,WHERE REDUCING NITROGEN POLLUTION IS A CRITICAL ENVIRONMENTAL GOAL.GIVEN THE POTENTIAL FOR SUBSTANTIAL NITRATETRANSPORTDURING LOW-FLOW CONDITIONS,POST-STORM ENRICHMENTOFFERS A UNIQUEOPPORTUNITY FOR POLLUTION MANAGEMENT THATCONVENTIONALPRACTICES MAY NOT ADDRESS. THE KNOWLEDGE GAINED FROM THIS PROJECT WILL ENHANCE OUR UNDERSTANDING OF NITRATE TRANSPORT IN AGRICULTURAL WATERSHEDS. IT WILLALLOW PREDICTIONS OF WHERE POST-STORM NITRATE ENRICHMENT IS LIKELY TO OCCUR AND PROVIDE INSIGHTS FOR PROPOSING POTENTIAL MANAGEMENT SOLUTIONS TO REDUCE NITROGEN POLLUTION MORE EFFECTIVELY.